Exodus 4:20-26

20So Moses took his wife and sons, put them on a donkey, and returned to the land of Egypt. And Moses took God’s staff in his hand.

21The Lord instructed Moses, “When you go back to Egypt, make sure you do before Pharaoh all the wonders that I have put within your power. But I will harden his heart so that he won’t let the people go.

22And you will say to Pharaoh: This is what the Lord says: Israel is my firstborn son.

23I told you: Let my son go so that he may worship me, but you refused to let him go. Look, I am about to kill your firstborn son!”

24On the trip, at an overnight campsite, it happened that the Lord confronted him and intended to put him to death.

25So Zipporah took a flint, cut off her son’s foreskin, threw it at Moses’s feet, and said, “You are a bridegroom of blood to me!”

26So he let him alone. At that time she said, “You are a bridegroom of blood,” referring to the circumcision.